1. Field of the Invention
The present invention relates to an apparatus for returning a turn indicator operating lever arranged such that the operating lever which has been actuated for the purpose of indicating the course of the vehicle when changing its advancing direction is automatically returned to the neutral position by turning the steering wheel in the opposite direction relative to the turning direction by which the course of travel is changed.
2. Description of the Prior Art
In the conventional apparatus of the type described above, a bracket is pivotally supported on a base plate in such a manner as to surround the periphery of a steering shaft around which a cylindrical canceling cam is positioned. The turn indicator operating lever is mounted on one side of the bracket, that is, one side of the steering shaft, and a ratchet which constitutes a part of the returning apparatus is provided on the other side of the steering shaft. The arrangement is such that, when the bracket is pivoted leftwardly or rightwardly by the action of the operating lever which is actuated for the purpose of indicating a left-turn or right-turn of the vehicle, a pawl of the ratchet is positioned on the locus of rotation of a cam projection of a canceling cam which rotates in response to the turning of the steering wheel, whereby, when the canceling cam is rotated in the opposite direction relative to the direction in which the lever has been actuated, the cam projection of the canceling cam presses against the pawl of the ratchet, thus causing the bracket and in turn the operating lever to be returned to the neutral position.
The above-described conventional arrangement, however, suffers from the following problem. Namely, since the bracket is provided in such a manner as to surround the canceling cam, it is necessary for the bracket to possess a disadvantageously large size, which fact unfavorably leads to an increase in the size of the returning apparatus as a whole.
In order to overcome the above-described disadvantage, the applicant of the present invention has previously proposed a device (Japanese Utility Model Application No. 165,187/1979) in which a bracket which pivots in response to the actuation of the operating lever is provided with a first gear, while a ratchet holder provided with a second gear which is meshed with the first gear is disposed pivotally and is equipped with a ratchet, and when the canceling cam is rotated in the same direction as the actuation direction of the operating lever, the ratchet acts such as to allow the canceling cam to rotate, while when the canceling cam is rotated in the opposite direction, the bracket is returned to the neutral position through the ratchet holder.
This arrangement, however, has a complicated gear structure, which creates the new problem that labor and time are required in assembly when, for example, a positioning operation is conducted. Further, since the second gear shaft is disposed between the operating lever and the steering shaft, the position where the operating lever is pivotally supported is unfavorably separated from the steering shaft.
Moreover, another structure has previously been proposed (U.S. Pat. No. 3,794,785) in which an operating lever and a single ratchet are provided on one side of a steering shaft. This structure, however, involves the same problem as that of the prior art described above, that is, the position where the operating lever is pivotally supported is excessively separated from the steering shaft.